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From: Thomas Gleixner <tglx@linutronix.de>
To: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>
Subject: Re: RFC: futex_wait() can DoS the tick
Date: Wed, 10 Jun 2015 20:27:10 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.11.1506102024380.3786@nanos> (raw)
In-Reply-To: <1433953758.6306.25.camel@gmail.com>

On Wed, 10 Jun 2015, Mike Galbraith wrote:
> Virgin source or kernels with zillion+ patches, doesn't matter.  To test
> virgin source earlier than EFI_STUB I had to pollute the source with
> EFI backports, but nothing else.
> 
> Just a sec while I check yet again that absolutely virgin master really
> really does stall....  Yup.  I pinned the tescase to CPU3..
> 
> LOC:       7432       5803       5418       6387       3371       3039       5757       3080   Local timer interrupts <== here
> LOC:       7560       6028       5632       6394       3538       3195       5937       3084   Local timer interrupts
> LOC:       7747       6135       5720       6394       3543       3262       6087       3086   Local timer interrupts
> LOC:       7930       6206       5785       6394       3571       3288       6303       3087   Local timer interrupts

So now it would be helpful to have a trace to see what CPU3 is
actually doing.

Thanks,

	tglx

  reply	other threads:[~2015-06-10 18:27 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-10 12:44 Mike Galbraith
2015-06-10 15:12 ` Thomas Gleixner
2015-06-10 16:29   ` Mike Galbraith
2015-06-10 18:27     ` Thomas Gleixner [this message]
2015-06-10 17:30   ` Mike Galbraith
2015-06-10 18:59     ` Thomas Gleixner
2015-06-10 19:15       ` Steven Rostedt
2015-06-10 19:32         ` Thomas Gleixner
2015-06-11  2:27       ` Mike Galbraith
2015-06-11  8:34         ` Thomas Gleixner
2015-06-11 11:41           ` Mike Galbraith
2015-06-11 13:13             ` Thomas Gleixner
2015-06-11 13:58               ` Mike Galbraith
2015-06-11 18:43               ` Mike Galbraith
2015-06-11 18:52                 ` Thomas Gleixner
2015-06-11 18:55                   ` Mike Galbraith
2015-06-11  7:35   ` Mike Galbraith
2015-06-11  7:43     ` Mike Galbraith

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